# Doubt about the derivation of the Callan-Symanzik equation

I was reading about the Callan Symanzik equation from Peskin and Schroeder. On page 411, they assume that since $$G^{(n)}$$, the connected Green's function is renormalized, the $$\beta$$ and $$\gamma$$ functions cannot depend on the cutoff $$\Lambda$$. Why is this so?

• Good question and good to doubt +1, but you may need to provide more detail discussions. and include the formulas, etc – wonderich Dec 23 '19 at 3:15